It is known to use in various data processing systems or in output printers a continuous sheet or web of paper, having individual sheets separated by perforations. After the information is conveyed to the sheet in any type of marked form, it is desired to separate these sheets for proper routing or dissemination. When the printing operation is completed, various bursting or sheet separating devices are used to tear the individual sheetings along the perforations and thereby separate them for further individual processing.
There are other type of paper separating machines that do not tear or separate by bursting a perforation but rather cut the sheets to a predetermined length, and then stack, collate or separate the sheets for subsequent processing. This type of device is often used in copiers or printers where paper roll is used and various lengths of printed or output sheets are desired. In high speed operations, such as in computer printers, electronic scanning apparatus or data processing equipment, this paper cutting operation is too slow and does not lend itself to be adapted for these uses. Instead most high speed electronic data processing systems utilize a continuous web of perforated sheets that are separated by various means or devices. Some of these devices include relatively expensive machine equipment that are difficult to maintain because of their complexity. Other devices containing bursting mechanisms for separating continuous webs have been found to be effective in the initial bursting of the perforation, but somewhat deficient in completing the tear along the remainder of the sheet.
Generally, the devices used commercially for separating continuous form webs comprise a three station or unit device; an inlet roller, an outlet roller, and intermediate said rollers a form bursting means. These devices generally program the inlet rollers at a speed less that the speed of the outlet rollers. Systems such as these are disclosed in U.S. Pat. Nos. 4,145,035; 4,118,022; 4,025,023; 3,968,916; 3,888,399 and 3,847,318. In these systems the continuous form web or strip is effectively pulled so that the pre-weakened portions or perforations transversely extending across the paper will become severed. The individual sheets then are collected at an outlet station after the outlet rollers. The burster station located intermediate the rollers is utilized to initiate the tear in the perforations or pre-weakened portions of the web. In computer output printer operations where the web speed-through is extremely fast, the bursting operation becomes a critical point in the entire process. Of additional importance to the initiation of the bursting process is the continuation of the tear to insure that the sheets are separated completely from the remainder of the paper web. Not only are the effectiveness of the bursting and complete tearing operations important, but as computer output printers progress in accelerated through-put, of equal importance is the speed of this paper separation. Many of the bursters known are not readily adaptable to this high speed operation nor can they be relied upon to perform effectively without operator attention at these maximum speeds. Additional drawbacks of heretofore known systems are the noise, reliability, bulkiness, and complexity of the bursting mechanisms. The present invention provides a novel mechanism that combines both the initial burst or paper breakthrough and the continuing tearing of the paper along the perforated edges. Also present in this invention is a relatively simple reliable structure for effectuating the separation required in the modern high speed processings systems in use commercially.
There are generally three burster mechanisms in use today embodied in separating equipment for continuous forms. In one embodiment, positioned between the input rollers and the output rollers is a bursting mechanism comprising axially mounted spheres to initiate the bursting process along the transverse lines of weakening of the web. In this prior art system, the web is fed between two pairs of feed rollers. A breaker roller is located in the path of travel between the two pairs of feed rollers for increasing tension along the line of web perforations and causing the webs to rupture along that line. A brake and clutch mechanism are connected to the first feed rollers to halt or slow these rollers at a predetermined time. The second set of feed rollers (or output rollers) are maintained at a fixed rotation thereby causing the tension resulting on the perforated web adjacent to the spheres to rupture. The most significant drawback to this type mechanism is that the spheres or burst balls do not effectuate a finished tear across the entire width of the web or perforation.
In the second embodiment used in the prior art, a V-shaped blade is positioned horizontally to the paper flow whereby the trip of the V will puncture through the perforations to initiate the separation. While this system generally does complete the tear across the paper width, it does not always successfully tear along the perforations.
In a further system used in the prior art, the output rollers are provided with a greater diameter than the diameter of the input rollers. Since it is usual that the output rollers are programmed at a speed in excess of the speed of the input rollers, this prior art system provided an approach where the diameter difference was substituted for the differential in speed to accomplish the longitudinal force required to burst the web perforations. This and some other known systems are not easily installed into existing high speed systems and suffer in cost due to complexity and difficulty in adaptations to present systems.